Satellite thermal observations of the Bezymianny lava dome 1993–2008: Precursory activity, large explosions, and dome growth

Abstract

[1] Fifteen years worth of Advanced Very High Resolution Radiometer (AVHRR) data is presented and used to quantitatively assess processes occurring at Bezymianny. This andesitic volcano is one of Kamchatka's most dangerous volcanoes with 16 eruptions in the last decade that have dispersed ash into North Pacific air routes. All known episodes of increased activity for which data were available were detected in band 3 (3.53-3.93 mm) AVHRR thermal data. Twenty-three peaks can be seen in the data; nineteen peaks correspond to known explosions, while the remaining three peaks correspond to known phases of dome growth that were not believed to have been accompanied by explosive activity. Start and end dates of extrusive phases defined by the thermal data are presented. Repose times between phases of extrusion vary from four months to just over two and half years with an average of just less than a year. Using rank-order statistics a 'maximum' time interval between consecutive explosions of 1288 ± 170 days is determined; this could serve as a cut-off time for declaring the current dome-growth activity over. The calculated cumulative erupted volume (0.28 km 3 ) and time-averaged extrusion rate (0.6 m 3 s (1) values that cluster around the mode of the data set prior to explosion, potentially due to endogenous dome growth, (2) upward trends that commence 15-20 days prior to explosion and reach sensor saturation levels are due to significant extrusion, and (3) a gradual upward trend that starts 5 days prior to explosion, probably due to ramping up of extrusion. This work shows that retrospectively analyzing and modeling of a volcano's thermal signal provides increased insight into its characteristic behavior. The methods used in this paper can be used at other dome-building volcanoes around the world. The insights presented here can be used to improve monitoring capabilities to aid in providing early warnings to large explosions at Bezymianny.

Thermal Remote Sensing for Global Volcano Monitoring: Experiences From the MIROVA System

“…Activity of Bezymianny consists of ongoing lava-dome growth inside a large horseshoe-shaped crater, accompanied by intermittent explosive activity and pyroclastic flows. As already advised by previous works (van Manen et al, 2010(van Manen et al, , 2013, some major explosions of Bezymianny are preceded by weeks of gradual increase of the thermal anomaly, thus constituting one of the most robust precursors for this remote volcano. In this case the thermal precursor occurred at a volcano characterized by a persistent, low level thermal activity, associated with the presence of degassing hot cracks and minor explosions.…”

“…In this case the thermal precursor occurred at a volcano characterized by a persistent, low level thermal activity, associated with the presence of degassing hot cracks and minor explosions. The increase of VRP prior to large explosions (Figure 7d) has been attributed to an increase in the dome extrusion rate (van Manen et al, 2010(van Manen et al, , 2013.…”

An experimental study of the surface thermal signature of hot subaerial isoviscous gravity currents: Implications for thermal monitoring of lava flows and domes

“…Lava domes often display an axisymmetric geometry, and have been modeled as gravity currents [ Huppert et al , 1982]. The approach of Harris et al [2007b] has previously been applied to retrieve the extrusion rate of a lava dome [ Harris et al , 2003; van Manen et al , 2010]. However, our model predicts that the thermal steady state, implicit in Harris' thermal proxy [ Harris et al , 1997a], will only be reached after years of continuous supply rate, due to the high viscosity of silicic magma (Table 4).…”

Analysis of Thermal Anomalies in Volcanic Areas Using Multiscale and Multitemporal Monitoring: Vulcano Island Test Case

“…In the first case, the low spatial resolution of satellite sensors does not allow the detection of thermal anomalies in small areas of the order of a hundred meters, even if the high frequency of repeated revisiting time allows daily monitoring. In the second case, the medium spatial resolution of sensors provides TIR measurements daily and can be used for quantitative analysis including measurement of surface temperatures [30,31], effusion rates [30][31][32][33], and heat flux measurements [31,34,35], but also in this case, the spatial resolution does not allow the detection of small thermal anomalies. In the last case, the high spatial resolution sensors are the most useful for quantitative measurements and analysis [21,28] even if their low temporal resolution revisiting time of 16 days makes them ineffective for real-time monitoring due to the transient nature of many volcanic processes.…”